Driving mechanism for lathes



(No Model.)

F. H. CRAFTS.

DRIVING MECHANISM FOR LATHES.

N0.499,159.. Patented June 6, 1893.

WIZJVZZ'SSES co. PNUTOLITHQ. wnsummou. a c.

UNITED STATES PATENT OFFICE.

FRANCIS H. CRAFTS, OF BUFFALO, NEW YORK.

DRIVING MECHANISM FOR LATHES.

SPECIFICATION forming part of Letters Patent No. 499,159, dated June 6,1893.

Application filed fieptember 21, 1892. Serial No. 446,438. (No model.)

To all whom it may concern:

Be it known that I, FRANCIS H. CRAFTS, a citizen of the United States,residing at Buffalo, in the county of Erie and State of New York, haveinvented certain new and useful Improvements in Driving Mechanism forLathes; and I do hereby declare the following to be a full, clear, andexact description of the invention, such as will enable others skilledinthe art to which it appertains to make and use the same.

This invention relates to improvements in driving mechanism for lathes,and consists in certainimprovements, as hereinafter set forth, in thegearing whereby the speed of the lathe may be instantly changed withoutsidewise shifting of the power-transmitting belt.

In the accompanying drawings, Figure 1 represents a front elevation of aportion of a lathe frame having my improvements applied thereto. Fig. 2represents a section thereof on the line a, a, of Fig. 1. Fig. 3represents a top plan View of a portion of a lathe-frame with myimprovements thereon.

In my construction, instead of the countershaft, 1, being located abovethe lathe frame, 2, it is mounted in suitable bearings, 3, near thebottom of the lathe frame, and has band pulleys, 4, with which beltconnection is had from the source of power.

5 represents a plural-stepped pulley keyed or otherwise secured uponsaid counter-shaft, 1; 6 represents a similar stepped pulley, reverselypositioned as customary, and located upon the spindle-shaft, 7. Theconnection between these stepped pulleys is had by a series of belts orbands, 8, 9, corresponding in number with and seated upon each stepthereof as shown. Ordinarily, where a plurality of pulleys, or steppedpulleys, are mounted on the respective shafts, a single belt has beenemployed which, as itis desired to change the speed of the machine, hasbeen shifted from one pulley, or from one step of the pulley, toanother. Manifest disadvantages, it is well known, result from thenecessity of so shifting the belt, especially where considerable changein speed of the machine is desired, and the time employed in so shiftingthe belt is a material loss, and the belt is injured by frequentsidewise shifting. By the employment of a distinct belt for each step ofthe pulleys employed in connection with a belttightener, or tighteners,by which the individual belt, alone,may be placed in operativeconnection with the respective pulleys and the remaining belts allowedto run idle according to the speed at'which it is desired to run themachine, a distinct advantage is socured in that a change of speed maybe instantly effected Without stopping the machine and without danger orrisk to the operative. Such a belt-tightening arrangement as has beenfound mosteffective Ihave represented in the drawings. Corresponding innumber with the number of, steps in the cones and with the beltsemployed, are belt-tighteners consisting of balls or disks, 10, whichmay be of a width equal to the Width of the respective belts; withsaidballs or disks 10 are engaged the inner angular ends, 11, of theoperative rods, 12,said ends, 11,havingslidable bearing within groovedboxes or braokets, l3, projecting inwardly from the rear of the frame ofthe lathe, the grooves, 14, in said boxes corresponding, or nearly so,in size with the size of the ends, 11, of the rods, 12, or disk journalsso as to permit of the free reciprocal movement therealong of the innerends of said rods 12 carrying said belt-tightener disks.

The belt-tightener-operating rods, 12, extend out beyond the front ofthe lathe frame, passing through a slot or opening, 15, therein asshown, and have at their outer ends suitable hand grasps or knobs, 16,by which they may be grasped by the operator to reciprocate said rodsback and forth to bring into contact I with or release from contact witheither of the belts as desired the respective belt-tighteners.

Figs. 2 and 3 of the drawings clearly indicate, in full and dottedlines, the operation of the tighteners. The front ends of the rods, 12,are somewhat enlarged, as shown in Fig. 2, and have on their under edgea series of teeth or serrations,17, which engage with the upper edge ofa metal plate, 18, attached to the front of the lathe frame andextending somewhat above the lower edge of the slot, 15, in said frame.By slightly raising the front ends of the operative rods, 12, said teethwill be released from engagement with the top edge of said plate, 18,whereupon said rods may be either pushed inward to release the disks,10, at the inner ends of said rods from .thus bevery effectually andexpeditiously tightening contact with the belts, or said rods may bedrawn forwardlyto bring the respective disks, 10, into frictional andtightening contact with said belts as the case may be; the outer ends ofsaid rods are then dropped to bring the teeth, 17, into engagement with'bination with the spindle-shaft, of a stepped the plate, 18, wherebysaid rods are securely held in their adjusted positions. The serrationsor teeth, 17, and plate, 18, at all times securely hold the rods, 12,and belt-tightener disks, 10, in their positions of adjustment. It willreadily be seen that by this arrangement the tension on all the beltscan be readily and instantaneously regulated and maintained at anydesired degree according to the character of the Work beingaccomplished; when the tool is taking a light out, the tension on thebelt need be. less than when a heavy cut is being taken, in which casethe rod' would be pushed in somewhat to release the tension on the beltof the tightener-disk, and, similarly, when the cut is heavier, the rodwould be drawn forwardly-to increasethe tension of thedisk on the belt;the speed of 1 engage said plate, and a suitable hand-grasp,

the rotation of the beltsand lathe spindle can regulated and maintainedaccording to re quirement.

By locating the counter-shaft below the spindle-shaft incontradist'inction to the location of the connter shaft above thespindleshaft,and the employment of a single sidewise-shiftable belt,Iavoid'the disadvantages of the belt pulling up on the spindle and'thc 1consequent tendency of the littingnp of the '1 tool, which results in anundue friction on the which produces more or less lost motion.

Having thus described my invention, what I claim is In a drivingmechanism for a lathe, the compulley located thereon, a counter-shaftjournaled in bearings parallel with said spindleshat't and havingsuitable power connection, a stepped cone pulley located on saidcounter-shaft, a series of belts or bands corresponding in number withand connecting the respective steps of said cone pulleys, averticallydisposed plate located adjacent an opening at the front of thelathe-frame, a series of belt-tighteners corresponding in numher withthe number of belts, and consisting of :rods having inner angular endswith disks thereon, and said rods extending outwardly therefrom inastraight horizontal line to the front and through the opening in thelatheframe and each having at its front end a notched or serrated underface and adapted to and a lathe having a series of grooved boxes toreceive and guide said belt-tighteners in their reciprocal movements,substantially as y and for the purpose set forth.

In testimony whereof I aifix my signature in presence of two witnesses.

FRANCIS; I-l. CRAFTS.

Witnesses:

C. J. HAMILTON, A. A. FRANKLIN.

